Vent-valve device



sept. 2s 19216., 1,601,167

` C. C. FARMER VENT VALVE DEVICE Filed Nov. 27. 1925 INVENTOR CLYDE'. C.FARMER ATTORNEY Patented Sept. 28, 1926.

Meldt? Y cnYDn o. FARMER, or'rrrrsnunen, rENNsYLvANrA, Assreivon To THEwnsrrne- House AIR BRAKE' COMPANY, er wirr/manine, rEr-nvsYLvAnrn, Acoaionnfrioiv OF PENNSYLVANIA.

VENT-VALVE DEVICE.

This invention relates to vent valve devices of the type Venfiployed inconnection with iluid pressure brake systems for eHect ing a localreduction in brake pipe pressure in an emergency application of thebrakes.

k10 ation of a vent valve device. v

In the accompanying drawing, the single ligure is a diagrammatic view,in section, 'of a portion of a fluid pressure brake'apparatus, includinga vent valve device and embodying my invention.

The apparatus shown in the drawing comprises a vent valve device 1, anemergency valve device 2, and a bra-ke pipe 8.

The vent valve device 1 comprises a casing having a chamber in which ismounted a vent valve holding cage. Said cage comprises a bushing portion4 and a valve holding portion 5 united by webbing 6. A vent valve 7 ismounted to reciprocate in` a bore of the valve portion 5 and isV adaptedto en gage a seat provided in the valve portion. A piston 8 is mountedto reciprocate in a bore of the bushing portion l and is connected tothe valve 7 by a stem 9.

The bushing portion l seats on an annular ledge of the valve casinglwith a gasket ring 10 interposed to make a tight joint. The valveportion 5 also seats on an annular ledge of the casing, a gasket ring 11being interposed between the ledge and the valve portion. A cap plate 12provided with a Agasket ring 13 closes the piston end of the valvecasing.

The emergency valve device 2 comprises a casing having a pistonchamber'lll connected to pipe 15 and containing a piston 16 and a valvechamber 17, connected to reservoir 18 and containing a slide valve 19adapted to be operated by piston 16.

Associated with the vent valve device 1 is a cut-out cock casing 20,containing a rotary cock 21 adapted to be operated by a handle 22. Inthe open position of the cock 21, valve chamber 23 of the vent valvedevice is connected through a cavity 24 with pipe 15 and piston chamber25 is connected through cavity 26 with a pipe 27 which leads to the seatof slide valve 19.

In operation, when the brake pipey 3 is charged with' iiuid underpressure, iiuid flows through pipe 15 to piston chamber 14C and; shiftsthe piston `16 toits inner position,.in which fluid is supplied frompiston chamber 14 through feed groove 28 to valve chamber 17 and thereservo-ir 18. The pipe 27 is blanked in this position of slide valve 19and vent valve 7 will be seated, with piston 8 in its upper position.

Upon a sudden reduction in brake pipe pressure, the piston 16 is shiftedto its outer position, as shown in the drawing, so that port 29 in slidevalve 19 registers with pipe 27. Fluid under pressure from the reservoir18 then flows through pipe 27 and cavity 26 of the cut-out cock 21 topiston chamber 25 and piston 8 is thereupon shifted, so as to open thevent valve 7 and thus permit fluid under pressure to be local ly ventedfrom the brake pipe 3 to atmospheric exhaust portBO. The piston 8 isprovided with a restricted po-rt 31, through which fluid from pistonchamber 25 and the' reservoir 18 is vented to the atmosphere by way ofport 30. lhen the pressure above the piston 8 has been reduced to apredetermined degree, the spring 32 returns the valve 7 to its seatedposition, cutting ott the further venting of fluid from the brake pipe.

The vent valve device may be cut out of action by turning the cut-outcock 21 to a position in which communication from piston chamber 25 topipe 27 is cut oli and also from brake pipe 3 to pipe 15. With pipe 27cut oit from piston chamber 25, there is a possibility of leakage fromreservoir 18 past the slide valve .19.- to pipe 27, and it pipe 27should thus be charged with fluid under pressure, then when the cock 21is I claim as new and desire to secure by Letters Patent, is:

1. The combination with a brake pipe,'a

brake pipe vent valve device, an emergency valve device operated upon areduction in brake pipe pressure for supplyingfluid under pressure tooperate said vent valve device, o1". a cut-out cocl; having a positionfor Cutting off communication through a passageway through which fluidunder pressure is supplied to said vent valve device and in whichposition the emergency valve device side ot' the passageway is connectedto the atmosphere. l

Q. A brake pipe vent valve device comprising?r a casing, a cage mountedin said casing and having a piston bushing` portion and a valve portionintegrally connected to said piston bushinfcr portion, a vent valvemounted and having a seat in said valve portion, a piston mounted insaid piston bushing portion, and a stem connecting said piston to saidvalve.

3. A brake pipe vent valve device comprisinga. casing a cage mounted insaid casing,- and having` a piston bushing portion` a vent valveportion, and sections integialhY connecting said bushingr portion rosaid valve portion, a gasket ringinterposed hetvreen said bushingportion and the casing, a gasket ring interposed betiveen said valveportion and the casing', a vent valve mounted in said valve portion, apiston mounted iu said bushing portion, and a stem connecting saidpiston to said valve.

In testimony vvhereotl I have hereunto set my hand.

CLYDE C. FARMER.

